A common way of thinking about links is that every link from another site that leads to yours is a vote for the popularity of your site. Every quality link you receive can improve your search rankings.

The quality of your inbound links is more vital than the quantity. The preferred and more valuable link is from sites that are relevant to your niche and with authority (highly regarded in the niche). A quality directory with relevant categories is another example. Just a few quality links with authority can have more value for your site than hundreds of lesser quality. Think of it like you do your personal business network. Both can have a strong effect on the success or failure of your business.